The ultimate goal of this program is to obtain data which can be used to evaluate the present or potential role of inhibitors of environmental chemical carcinogens. Pursuant to this goal are several major objectives. The first is to determine the mechanism of inhibition of chemical carcinogenesis by antioxidants and other compounds found to exert an inhibitory effect. The second is to determine conditions under which inhibition occurs including parameters which will predict the host's capacity to utilize specific inhibitory mechanisms. The third is to determine chemical characteristics which control the ability of compounds to inhibit chemical carcinogenesis. The mechanism of inhibition of polycyclic hydrocarbon carcinogenesis by antioxidants will be investigated. Studies of the manner by which disulfiram and butylated hydroxyanisole (BHA) cause decreased binding of benzo(a)pyrene metabolites to various cellular marcomolecules will be carried out. These include investigations of the effects of these antioxidants on enzyme systems. In addition, efforts at demonstrating direct interactions between antioxidants and reactive metabolites of chemical carcinogens will be made.